Banksia epica
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| Banksia epica A.S.George |
Banksia epica is a species of shrub in the plant genus Banksia. Recently discovered and little studied, it is known only from two populations in the remote south east of Western Australia. It grows as a spreading bushy shrub up to two metres (6 ft) high, with large creamy-yellow flower spikes. First collected in 1973 but not recognised as a new species until 1988, it is placed in Banksia subgenus Banksia, section Banksia, series Cyrtostylis.
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[edit] Description
B. epica grows as a spreading bushy shrub with many branches, from 30 centimetres (12 in) to 3½ metres (11½ ft) tall. The bark is grey and fissured. The leaves are wedge-shaped, 1½ to 5 centimetres (½–2 in) long and 6 to 15 millimetres (1/8–2/3 in) wide, with serrated margins. Flowers occur in Banksia's characteristic "flower spike", an inflorescence made up of hundreds of pairs of flowers densely packed in a spiral round a woody axis. B. epica's flower spike is a creamy yellow colour, cylindrical, 9 to 17 centimetres tall and around 6 centimetres in diameter. The fruiting structure is a stout woody "cone" embedded with up to 50 follicles, and has a hairy appearance caused by the persistence of old withered flower parts.[1]
B. epica has a very similar appearance to its close relative B. media (Southern Plains Banksia), which also occurs in the area. It differs from B. media in having slightly shorter leaves and larger flowers. In addition, the persistent flower parts on B. epica's fruiting structures are curled and point upwards, whereas they are straight and point downwards on B. media.[2]
[edit] Taxonomy
[edit] Taxonomic history
The first European to sight B. epica may have been the explorer Edward John Eyre, who recorded sighting "stunted specimens" of Banksia as he was nearing the western edge of the Great Australian Bight on 1 May 1841:[3]
- "One circumstance in our route to-day cheered me greatly, and led me shortly to expect some important and decisive change in the character and formation of the country. It was the appearance for the first time of the Banksia, a shrub which I had never before found to the westward of Spencer's Gulf, but which I knew to abound in the vicinity of King George's Sound, and that description of country generally. Those only who have looked out with the eagerness and anxiety of a person in my situation, to note any change in the vegetation or physical appearance of a country, can appreciate the degree of satisfaction with which I recognised and welcomed the first appearance of the Banksia. Isolated as it was amidst the scrub, and insignificant as the stunted specimens were that I first met with, they led to an inference that I could not be mistaken in, and added, in a tenfold degree, to the interest and expectation with which every mile of our route had now become invested."[4]
Eyre is thought to have been passing through the Toolinna Cove sand patch at the time of writing.[5] B. epica and B. media are the only Banksia species that occur at that location,[1] and both have a habit and form that fulfills Eyre's description. As he did not collect specimens, so it is impossible to determine what species he saw.
The first herbarium collection of B. epica was not made until October 1973, when Ernest Charles Nelson visited Toolinna Cove to collect specimens for a taxonomic revision of Adenanthos. He became interested in the disjunct plant distributions there, and ended up collecting specimens of a range of plant species.[5] On 22 October, he collected a specimen of B. epica in old flower, but he did not recognise it as a new species. It was lodged in the herbarium at Canberra labelled as B. media.[3]
In 1985, two volunteer field collectors for The Banksia Atlas project, John and Lalage Falconer of Esperance, collected at Point Culver and became convinced that the location contained three Banksia species rather than two. On 9 January 1986 they returned to the location, collecting leaves and old flowers of what they thought was an undescribed species; however they were unable to collect fresh flowers or fruit because the species flowers only from April to June. The Falconers' specimens did indeed suggest that a new species had been discovered, but they were insufficient for formal publication. Early in May the following year, John Falconer drove over 2000 kilometres on unsealed tracks from Warburton to Point Culver and back again, in order to collect fresh flowers and fruit of the purported new species.[2] Based on these specimens, Alex George begin preparing a formal description of the genus. During his research, he discovered that Nelson's Toolinna Cove specimen was also referrable to the undescribed species. In the absence of any genuine B. media specimens from Toolinna Cova, George inferred that only B. epica occurred there, and that Eyre must have sighted B. epica in 1841. In 1988, he published a formal description of the species, naming it Banksia epica in reference to the two "epic" journeys of Eyre and Falconer.[3] Thus the full name for the species is Banksia epica A.S.George.[6] A 1991 survey subsequently found both B. epica and B. media at Toolinna Cove.
[edit] Current treatment
George placed B. epica in Banksia subg. Banksia, because its inflorescences take the form of Banksia's characteristic flower spikes; Banksia sect. Banksia because of its straight styles; and Banksia ser. Cyrtostylis because it has slender flowers.[3] Its closest relatives are B. praemorsa (Cut-leaf Banksia) and B. media, both of which have shorter flowers and a smaller pollen-presenter than B. epica. In addition, B. praemorsa differs in having a hairless perianth, and B. media has larger, more undulate leaves.[1] Recent cladistic analyses of Banksia confirmed B. epica's placement in Cyrtostylis alongside B. praemorsa and B. media, despite finding George's conception of Cyrtostylis to be "widely polyphyletic".[7]
B. epica's placement within Banksia may be summarised as follows:
- Genus Banksia
- Subgenus Banksia
- Section Banksia
- Series Salicinae
- Series Grandes
- Series Banksia
- Series Crocinae
- Series Prostratae
- Series Cyrtostylis
- B. media - B. praemorsa - B. epica - B. pilostylis - B. attenuata - B. ashbyi - B. benthamiana - B. audax - B. lullfitzii - B. elderiana - B. rosserae -B. laevigata - B. elegans - B. lindleyana
- Series Tetragonae
- Series Bauerinae
- Series Quercinae
- Section Coccinea
- Section Oncostylis
- Section Banksia
- Subgenus Isostylis
- Subgenus Banksia
[edit] Distribution and habitat
B. epica is known only from two populations on the Nullarbor Plain near the western edge of the Great Australian Bight. The main population occurs about 30 kilometres west of Point Culver; there were over 2000 plants there when surveyed in June 1989. A smaller population occurs about 70 kilometres further east at Toolinna Cove; when surveyed in August 1991, this locality had around 350 plants. This latter population represents the easternmost limit of the western Banksia species; east of Toolinna Cove no Banksia species occurs for over 900 kilometres.
Both of the localities in which B. epica is known to occur are unusual in having cliff-top dunes of deep, white siliceous sand. Cliff-top dunes are uncommon along the Great Australian Bight, and most sand on the Nullarbor is heavily calcareous. As Banksia species are intolerant of calcareous soils, and are not adapted to long range seed dispersal, these populations appear to be reproductively isolated. Nelson has suggested that there was once a continuous strip of siliceous sand along the coast, providing an extensive and unfragmented habitat for B. epica; rises in the sea level had submerged this strip, leaving only the cliff-top dunes as suitable habitat. The fact that the resultant isolated populations have not perceptibly speciated since then suggests that the species has been fragmented for only a short time, perhaps only since the Last Glacial Maximum.[5]
B. media and B. epica are the only Banksia species to grow on alkaline soil.[8]
[edit] Ecology
B. epica lacks a lignotuber, so it is thought to be killed by fire. Like all Banksia species, however, it is adapted to release its aerial bank of seeds following a bushfire, and so regenerates rapidly. Known pollinators include the New Holland Honeyeater and the Yellow-rumped Thornbill.[9] However detailed observational studies of other banksia species have generally revealed a wide range of invertebrate and vertebrate pollinators involved.
Because so few populations are known, B. epica has been declared "Priority Two - Poorly Known Taxa" under the Wildlife Conservation Act 1950. It is not considered to be under threat, however, because both populations occur within the Nuytsland Nature Reserve, and are undisturbed and healthy.[9] Furthermore, the area in which it occurs is poorly surveyed, so it is possible that other populations exist.[2]
[edit] Cultivation
B. epica is fairly new to cultivation. Kevin Collins of the Banksia Farm in Albany, Western Australia pioneered cultivation of the species, growing it in loamy clay or sandy gravel. It has shown excellent tolerance for alkaline soils, succeeding in sandy, alkaline soil near the coast between Mandurah and Kwinana. It has also been grown successfully for several years in well-drained beds at the Australian National Botanic Gardens in Canberra, also seeds planted in less well drained beds died. Propagation is by seed or cuttings.[10][11]
[edit] References
- ^ a b c George, Alex S.. (1999). "Banksia". Flora of Australia Volume 17B: Proteaceae 3: Hakea to Dryandra: 175–251. Ed. Wilson, Annette. CSIRO Publishing / Australian Biological Resources Study. ISBN 0-643-06454-0.
- ^ a b c Taylor, Anne and Stephen D. Hopper (1988). The Banksia Atlas (Australian Flora and Fauna Series Number 8). Canberra: Australian Government Publishing Service. ISBN 0-644-07124-9.
- ^ a b c d George, Alex S. (1988). "New taxa and notes on Banksia L.f. (Proteaceae)". Nuytsia 6 (3): 309–317.
- ^ Eyre, Edward John (1845). Journals of Expeditions of Discovery into Central Australia, and Overland from Adelaide to King George's Sound, in the Years 1840-1: Sent by the Colonists of South Australia, with the Sanction and Support of the Government: Including an Account of the Manners and Customs of the Aborigines and the State of their Relations with Europeans. London: T. and W. Boone.
- ^ a b c E. Charles Nelson (1974). "Disjunct plant distributions on the south-western Nullarbor Plain, Western Australia". Journal of the Royal Society of Western Australia 57 (4): 105–117.
- ^ Chapman, Arthur D.. (1991). "Banksia epica A.S.George". Australian Plant Name Index (Australian Flora and Fauna Series 12—15). Canberra: Australian Government Publishing Service. Retrieved on 2006-12-01.
- ^ Thiele, Kevin, Pauline Y. Ladiges (1996). "[www.publish.csiro.au/?act=view_file&file_id=SB9960661.pdf A Cladistic Analysis of Banksia (Proteaceae)]". Australian Systematic Botany 9 (5): 661-733. Retrieved on 2006-12-15.
- ^ Lamont, Byron B. and S. W. Connell (1996). "Biogeography of Banksia in southwestern Australia". Journal of Biogeography 23 (3): 295–309. DOI:10.1046/j.1365-2699.1996.00027.x.
- ^ a b Gillian F. Craig and Coates, David J. (2001). “B. Priority 2 Taxa”, Declared Rare and Poorly Known Flora in the Esperance District. Bentley, Western Australia: Department of Conservation and Land Management. ISSN 0816-9713. Retrieved on 2006-08-31.
- ^ Banksia epica. Association of Societies for Growing Australian Plants (ASGAP). Retrieved on 2006-08-30.
- ^ Liber, C. (2002). "[farrer.csu.edu.au/ASGAP/banksSG/banksiasg-4-1.pdf Banksia epica, media & praemorsa in ANBG, Canberra]" (PDF). Banksia Study Group Newsletter 4 (1): 4. ISSN 1444-285X. Retrieved on 2006-12-15.
[edit] External links
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Wikimedia Commons has media related to: |
- Banksia epica at Florabase, Department of Environment and Conservation, Western Australia.
- Banksia epica at Flora of Australia Online, Department of the Environment and Heritage, Australia.
